Apple is investigating, say users on company's support forum

Apple is investigating reports of shorter battery life on Mac laptops that customers have upgraded to OS X Mountain Lion, according to the company's support forum.

Owners of MacBooks, MacBook Pros and MacBook Airs began reporting problems shortly after Mountain Lion launched on July 25. The longest thread on Apple's discussion forum thus far kicked off on July 31. As of Monday, it included more than 460 messages that had been viewed nearly 28,000 times. Both numbers are high for an Apple support thread.

According to user reports, battery consumption is considerably faster than before the upgrade to Mountain Lion, with a resulting shorter battery lifespan. Others claimed that even after a full charge, their laptops were reporting significantly less time remaining compared to when they were running OS X Lion or Snow Leopard.

"Bought a 13[-in MacBook] Air with Lion installed, and when fully charged, and nothing running it reported 6 hours 45 minutes remaining," said someone identified as "Salty777" in a message posted to the forum today. "After upgrading to Mountain, in exactly the same condition, it's reporting 4 hours 30 minutes remaining."

Others said their battery life had been slashed as much as 50 percent after installing Mountain Lion.

Some users said that they had been contacted by Apple's technical support, who asked that they submit Activity Monitor logs and other information for examination.

"They sent me a data capture app which records background activity that they will use to find the issue," noted "stevo_c" in a message early today. "I can confirm this is definitely a software (OS) issue as the guy that was dealing with me said that an update will be issued via the app store as soon as they can work a fix."

An opt-in poll conducted by the Apple-centric blog 9to5Mac.com said over a third of the 1,800 who took part reported battery issues after upgrading to Mountain Lion.

Apple has faced battery life complaints before, most recently last fall with the then-new iPhone 4S, which owners said was racing through its power supply at a prodigious rate.

If the problem can be addressed with a software update, as "stevo_c" said, that update could appear this month. Last year, Apple shipped the first update for Lion, OS X 10.7.1, four weeks after the operating system went on sale; in 2009, Apple was even faster, releasing 10.6.1 just 12 days after the debut of Snow Leopard.

Unlike Microsoft, Apple does not keep a regular update schedule for its operating system, and does not alert users before it ships bug fixes and security patches.